I am an app developer and was actually thinking of making one myself.

The one problem is that you could only target the existing lucid dream community, as you would indefinitely get bad reviews from the non-members, frustrated because they can't LD automatically just by running the app.

The iPod itself could be a RC (if you can't unlock it, then it's probably a dream).

I believe it would be possible to implement features (like flashing lights during an REM cycle for DILDING), a CANWILD alarm right before a REM cycle for WILDING.
Isochronic tones, hypnotizing mp3's, binaural beats would all be useful features too.
Even access to useful tutorials (the best from this site) inside the app would be useful.

oh,
and a kitchen timer, white noise and a dream journal that can be uploaded to dreamviews.